Carrying agent influence on the ruthenium catalyst activity of the ammonia synthesis

The paper examined the catalysts of low-temperature ammonia synthesis Ru-Cs/Sibunit in which Sibunit, mesoporous carbon carrying agents, vary considerably in specific surface area and pore volume, but the pore sizes are similar. According to Raman spectroscopy, the Sibunit structures are same. Applied ruthenium dispersiveness, determined by CO chemisorption, are also close (similar to 13 - 16%) for all the examined catalysts. The difference in the activity of the samples is due to the different direct contact probability of the particles of ruthenium and modifier (CsOx). This probability decreases with increasing specific surface area (S-BET Sibunit) that are supposed to cause the decrease of catalyst activity on high-superficial Sibunit in the ammonia synthesis reaction. (C) 2015 The Authors. Published by Elsevier Ltd.